Reinforced plating barrel

ABSTRACT

A PLATING OR METAL FINISHING BARREL OF GENERALLY POLYGONAL SHAPE HAVING A WORK RECEIVING CAVITY FORMED BY RECTANGULAR SIDE PANELS AND END WALL. THE SIDE PANELS ARE SECURED IN SIDE EDGE-TO-SIDE EDGE ALIGNMENT WITH THE END WALLS SECURED TO THE END EDGES OF THE PANELS. A REINFORCING PLUG OF SUBSTANTIALLY THE SAME MATERIAL AS THE SIDE PANELS AND END WALLS IS FRICTION WELDED AND THEREBY FUSED TO ONE END WALL AND THE MEETING EDGE OF A SIDE PANEL SIDE EDGE.

y 20, 1971 A. SINGLETON REINFORCED PLATING BARREL Filed Nov. 6, 1968 INVENTOR. ALBERT SINGLETON FIG-5 ATTORNEYS.

United States Patent 3,594,297 REINFORCED PLA'IING BARREL Albert Singleton, 7360 Brookside Parkway, Middleburg Heights, Ohio Filed Nov. 6, 1968, Set. N0. 773,929 Int. Cl. C23b /78 U.S. Cl. 204-213 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Plating or metal finishing barrels are extensively used for electroplating, cleaning, phosphating or otherwise treating a variety of articles. For convenience in referring to the structure to perform these operations, plating barrel will be used. The barrels are commonly polygonal shape and usually have five sides plus a door.

A plating barrel of the type commonly used is disclosed and described in US. Pat. No. 2,886,505 issued May 12, 1959 to A. Singleton et al.

The barrel heretofore used generally comprises a plurality of flat rectangular side panels having side and and edges. The panels are secured to each other at the meeting side edges of adjacent panels. This securement is generally accomplished by a bead of weld material laid along the meeting edges. In the case of barrels composed of thermoplastic materials, a thermoplastic weld material is employed.

A similar weld material is used to attach the end walls to the end edges of the side panels. These end walls not only enclose an article receiving area or internal cavity, but also are generally circular and have grooves to accommodate and endless belt attached to a drive means which rotates the barrel during the plating process. Balllike electrodes are inserted into opposite ends of the barrel to provide the electrical current for the plating operation.

Severe physical and chemical abuse must be withstood by any operable barrel construction. Chemical attack by the various solutions used in plating the articles can be minimized by the use of a thermoplastic material, such as polyethylene or polypropylene. These thermoplastics are of course inert to attack by the chemicals used in the plating process. Physical abuse, however, must be withstood by the barrel construction itself. In thi regard, many plating barrels are made of stainless steel, Monel and Carpenter No. stainless steel.

During a conventional plating operation, the articles in the barrel and therefore the barrel itself are subjected to the following steps: cleaning, pickling, plating and washing. Each of these steps requires the barrel to be lowered into a separate vat or bath containing a cleaning solution, wash solution and so on. Often the temperature of the liquid in the individual vats may vary from room temperature to as high as 220 F. These radical temperature changes have been found to seriously impair the strength and therefore the life of the weld between adjacent side panels and side panels and end walls. As the barrel parts, for example the side panels and end walls expand and contract due to the temperature fluctuations,

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the weld between them frequently fails, the barrel separates, breaks or cracks and the articles are dumped into one of the plating vats or on the floor with varying degrees of damage.

In addition to the severe temperature fluctuations, the barrel end walls which are attached to the end edges of (1) the ball-like electrodes striking the barrel sides and (2) the articles themselves tumbling in the revolving barrel and with subsequent striking of the side panels.

In attempting to rigidify the overall barrel construction above described, the prior art has employed supporting ribs and rods, either individually or in combination. Supporting ribs (generally of a material similar to that of which the barrel is constructed) are secured to the meeting side edges of two or more side panels. These are either attached to or made integral with the side panel side edges. The ribs are used to cover the entire length of the side edge or alternatively a plurality of them are disposed along the length of the side edge.

Supporting rods, for example, stainless steel rods, are frequently used as additional supporting structures. They usually extend the full length of the side panel as well as having their ends extending through the end walls. By being threaded at opposite ends, they may be secured to the end wall by nuts on the outer face of the end walls.

SUMMARY OF THE INVENTION This invention is directed to a plating barrel of known construction and discussed above but including the improvement of reinforcing plugs frictionally welded and therefore fused to the meeting edges of adjacent barrel side panels. The plugs are further welded and fused to the barrel end walls which are attached to the end edges of the barrel side panels.

The reinforcing plug is generally composed of the same material as is the barrel, Le. a thermoplastic such as polyethylene or polypropylene. This insures that a homogeneous and rigid fusion will take place between the plugs, end walls and side panels.

It has been found that use of a thermoplastic reinforcing plug fused to the barrel end walls and side panels substantially increases the overall strength of the barrel. Since the plug, by means of friction Welding, is actually fused to the side panels and end walls it becomes integral with each of them. Since the plug passes through and is fused to the end wall and side panels it prevents any cracking or separation at the junction thereof and keeps the barrel intact even while being subjected to severe temperature fluctuations and/or physical pounding from the electrodes or articles being plated.

It is an object of this invention to provide a plating barrel of improved strength and operating life.

An other object is to provide a barrel of thermoplastic material With the side panels and end walls bonded together by a friction plug weld.

Another object is to provide a barrel for tumbling articles with the side and end wall joined by a plug friction weld extending through an opening in the end wall into a depression in the end edge of the side wall.

DESCRIPTION OF THE DRAW'INGS FIG. 1 is a front elevational view of a plating barrel and drive means;

FIG. 2 is an end elevational view partially in section, of the barrel of FIG. 1 taken along line 2-2 of FIG. 1;

FIG. 3 is a side elevational view of the barrel;

FIG. 4 is an exploded view of a side panel, an end Wall and a plug prior to assembly; and

FIG. 5 is a side elevational view in section of the panel, end wall and plug assembled in position.

PREFERRED EMBODIMENT While the barrel disclosed in this invention could be used in any number of operations, such as a mixing barrel or a barrel for agitating parts in a degreasing fluid, the preferred embodiment is a barrel to be used in an electro-plating apparatus.

As herein shown, the barrel, indicated generally at 10, is supported on a standard frame 12 which includes a U-bolt support 14 for suspending the barrel within various electrolitic baths or cleaning solutions. The barrel .10 is supported from the frame 12 by means of a horizontal shaft 16, a pair of identical spaced circular upper pulleys 18 and a pair of identical corrosion-resistant endless V-belts 20.

The rotatable shaft 16 is journaled for rotation by appropriate metal bearings disposed on the frame 12 and may be driven by gears or belts (not shown) as desired. The V-belt 20 drives the lower pulleys 22 which are also the end walls of the barrel. Circumferential grooves 23 are formed in the end walls 22 to receive the V-belt.

Electrode means are provided for the rotatable barrel 12, including a pair of flexible, low resistant electrical conduits or cables '24 of large cross-sectional area having removable metal electrodes 26 near the bottom of the barrel, the metal portion of each conduit above the electrodes being completely covered by a tubular layer of flexible corrosion resistant rubber or plastic material.

An enclosure is formed by a plurality of substantially rectangular panels 28 joined along their edges. As shown in the lower part of FIG. 2, the junction of each pair of adjacent panels includes an enlarged portion such as a ridge or rib 30. The material used to form the panels and ribs may be any convenient material suitable for the welding process which will subsequently be outlined. The joining of two side panels and a preformed rib, per se, may be made by any conventional welding process.

FIG. 2 shows a plating barrel which is hexagonal. There are five panels 28 and a door 32. With the door in place, as seen in FIG. 2, the barrel may be rotated by the V-belts 20 and due to the apertures or pores 33 in each of the panels and the door, fluid will be circulated through the barrel.

Three identical clamps 34 are provided for holding the door in its closed position. Each clamp comprises a resilient metal strip of uniform width and thickness which is bent to form flat end portions 36 and 38 and a flat intermediate portion 40 integrally joining said end portions. Said end portions are inclined at an angle of about 120 relative to the intermediate portion so as to be parallel to the side panels 28 as they are joined in this particular embodiment, FIG. 2. A flange 42 is formed on one end of the strip to latch or hook behind one of the ridges bordering the door opening. A generally rectangular block 44 of suitable corrosion-resistant material is rigidly connected to the clamp 34 for locking behind another of the ribs 30 bordering the door opening. The metal portions of each clamp 34 are completely covered by a layer or coating of generally uniform thickness. The layer may be made of any suitable material which is corrosion resistant and twin not be damaged by strong acids which may be encountered by the barrel.

Viewing FIG. 4, panels 28 are shown in juxtaposed relationship to an end wall 22 with a cylindrical plug 46 placed in position to be inserted into an aperture 48 through the end wall 22 and into a cone-shaped depression 50. The plug 46 will be forced into the aperture 48 and the depression 50 by axial force and because of this an opening 52 is provided through the plug to allow gases to escape from the depression 50 to the atmosphere. This reduces the back pressure of any gases trapped in the depression and allows easier insertion of the plug 46. The aperture 48 is shown to be tapered in FIG. 4, however, a cylindrical opening could be employed if it were prop- 4 erly dimensioned to closely fit around the cylindrical plug 46.

The process for attaching the end wall 22 to the side panels is called friction welding or spin welding. The forward end of plug 46 is inserted into the depression 50 through aperture 48 and some power tool is employed to abut the outer end 54 of the plug and apply a relatively high speed rotation to the plug with respect to the depression 50. When this is done, the frictional heat generated at the surface of the parts being joined rapidly softens the juxtaposed surfaces by local frictional heat and as the plug is forced inwardly of the depression 50, this heat is suflicient to cause an almost instantaneous welding of the contacting materials so that a strong and rugged joint immediately results. As described, the weld can be efected within a matter of a few seconds and is immediately of strength equal or superior to weld connections made by other less convenient and more complicated methods.

The drawings illustrate the barrel and plug as plastic materials. However, this is merely a convenient device for illustration, in practice many metals are suitable for barrel construction (stainless steel, Monel, Carpenter No. 20 stainless steel, etc.). It has been found that metals of low melting temperatures work substantially the same as plastics except that greater force is usually required to rotate the metal plugs. Metals of higher melting points often require welding flux for proper bonding.

FIG. 5 shows the plug inserted within the depression 50 with the shading indicating the welded plug 46 is substantially integral with the remainder of the plastic materials. The plug 46 is preferably of the same material as the end wall 22 and the panels 28.

It has been found that because of the relative masses of the plug 46, end wall 22 and panels 28, the plug melts to a greater extent than the more bulky parts. Thus, upon freezing the plug is at a higher temperature than any of the parts to which it is welded. The thermal contraction which results with temperature equalization draws the panels and end wall into eveen closer engagement with a resulting stronger structure.

In the conventional electro-plating process the barrels 10 are subjected to much physical abuse. The items contained in the barrel may be rather heavy and as the barrel rotates these items tumble about inside, subjecting the interior to continuous random hammering action. In addition, electrical contact with the work is maintained by the heavy ball-shaped electrodes 26 attached to the flexible cable 24. These ball-shaped electrodes similarly tumble about inside the rotating drum, pounding upon the walls as they fall. This continual physical bearing eventually causes weakening and breakage of the drum resulting in loss or damage of the work, necessitating frequent repair and causing an accompanying economic loss. Besides this physical abuse, the drums are generally subjected to rapid temperature fluctuation as they are transferred from bath to bath. The resulting expansion and contraction of the drums causes weakening of the joints particularly in the area of the door ribs, similarly resulting in economic loss due to breakdown.

In certain prior art devices it has been necessary to bolt the drum together by means of long metal rods joining the opposite ends of the drum. This construction is used where extra strength is necessary or where the drum must be disassembled frequently. Even when these threaded rods are made of the most durable materials available, certain types of stainles steel or titanium for example, they tend to become bi-polar because of the electric current flowing across them through the plating solution. Eventually the rods, particularly the ends, become eaten away to the point that their physical strength is destroyed resulting in damage to the drum. It has been found that the points of greatest weakness are at each junction of the end plates, side walls and ribs, with maximum weakness exhibited at the opposite ends of the two door ribs. It was discovered that drilling an inwardly tapered hole particularly through the end wall at each weak point such that the axis of the hole or depression 50 lies along the junction of the two side panels or in the case of the door rib, lies parallel to the length of the door rib and the center line of the face of the door rib which is in contact with the side panel, With a plug welded in position at the opposite ends of each rib, as outlined in the above disclosure, the drums strength with respect torsion exerted by the drive means through the end plates, as well as the ability to withstand heavy blows from Within is greatly enhanced. This is particularly true with respect to the door ribs which have one less integral supporting member than the other barrel ribs. Similarly the welded plugs serve to eliminate cracking which results from shearing forces created at each joint between the ribs, side panels and end walls when the drums are subjected to rapid temperature fluctuation.

In practice it has been found that the door items tend to buckle inwardly, eventually distorting to such an extent as to require replacement. The buckling further causes a shearing force at the interface between the door rib and the side wall. To eliminate these difficulties, it has been found that the ribs juxtaposed to the door opening which are held in place by friction welded plugs through both of the ends are extremely long lived. The plugs tend to eliminate the destruction of the door ribs by shearing forces and the additional width makes the door panel symmetrical about any plane containing two of its three orthogonal center lines. Thus the door panel may be periodically reversed so as to cause periodic reversal of the aforementioned buckling, eliminating the necessity for frequent door replacement.

Another feature of this invention is to provide a groove 56 in the end wall 22, see FIGS. 4 and 5. The ends of the panels 28 are inserted into the grooves 56 to provide radial stability of the barrel. The groove and plug combination have been found to be extremely effective in this type of rotating operation and undesired distortions or unexpected barrel failure have been largely eliminated.

As will be apparent to those ordinary skill in the art, certain modifications may be made in this invention without departing from the spirit of the invention. It is not the intention of the inventor to be limited by the illustrated embodiment nor the language employed in describing it. Rather it is the desire of the inventor to be limited only by the scope of the appended claims.

The invention claimed is:

1. A plating apparatus of a thermoplastic material comprising a barrel of polygonal shape having an internal cavity and a door opening;

said cavity defined by a plurality of flat rectangular side panels having side and end edges;

said panels positioned in generally meeting side edge-toside edge alignment With means securing each of these meeting edges to the other;

at least one supporting rib attached to and thereby rigidifying each of said meeting edges of said panels; end walls attached to said end edges of said side panels whereby said side panels and end walls form said cavity; a door in place of one side panel; wherein the improvement comprises at least one thermoplastic reinforcing plug frictionally welded and thereby fused to one of said end Walls and a portion of the meeting edges of at least two of said side panels;

said plug being positioned transverse to the plane of said end wall.

2. The improvement of claim 1 in which the thermoplastic material of which said barrel and plug are composed is polypropylene.

3. The improvement of claim 1 in which said supporting ribs are integral with and extend the length of said side panel meeting edges and with said plug further being friction welded and fused to said rib.

4. The barrel of claim 1 wherein the door is reversible.

5. A barrel for tumbling articles therein, comprising:

a plurality of side panels joined along their side edges to form a polygonal enclosure;

a door in place of one side panel;

end walls secured to the end edges of the panels by plug welds, and

The plug welds including a plug extending through an aperture in the end wall to contact two contiguous side panels and being bonding to both the wall and the panels, said plug welds having been formed by spin welding a cylindrical plug into an aperture of substantially uniform taper from an outer diameter greater than said plug to an inner diameter less than said plug.

6. The barrel of claim 5 wherein the plug extends into a depression in a panel.

7. The barrel of claim 6 wherein the depression is defined by a cone-shaped surface coaxial with the aperture.

8. The barrel of claim 7 including an opening extending through the plug to provide a passageway between the atmosphere and the innermost portion of the depression.

9. The barrel of claim 8 wherein at least two plugs contact each end edge of each side panel.

10. The barrel of claim 8 wherein one plug extends into a depression formed at the junction of the joined side edges of the panels.

References Cited UNITED STATES PATENTS 2,886,505 5/1959 Singleton, et a1 204-213 3,394,071 7/1968 Gill 204- 213 3,439,900 4/1969 Gill 204--213 JOHN H. MACK, Primary Examiner T. TUFARIELLO, Assistant Examiner U.S. Cl. X.R. 15 6-73 

